Dan,
You don't say where in Michigan, but have you noticed a few boats? Take a hint there.
Fog the engines. This will coat the corrosion prone surfaces with oil. The main engine is electronic fuel injection, but it will still benefit from Sta-Bil or Seafoam in the fuel. When you get it put to bed, then fog the generator. When you choke it with fog or shut it down, then look for a fastener in the bottom of the carburetor and loosen that. let it drip until it stops and then take it back tight. That should adequately drain the carburetor for the winter.
Have the fuel tanks as full as is practical to minimize the tank "breathing" that will invite moist air into the tanks.
Matt